This gist is created in response to a request for debugging backlink on a mailing list

backlink.py

import logging
from urllib2 import urlopen, Request
import re
from bs4 import BeautifulSoup as Soup
from optparse import OptionParser
from collections import namedtuple, Mapping
import sys

__author__ = "Supreet Sethi <supreet.sethi@gmail.com>"
__copyright__ = "Copyright (C) 2014 Supreet Sethi"
__license__ = "Public Domain"
__version__ = "1.0"
__doc__ =""" This a backlink checker. It allows mass checking of a backlinked URL"""
log = logging.getLogger('backlink-checker')



def namedtuple_with_defaults(typename, field_names, default_values=[]):
    T = namedtuple(typename, field_names)
    T.__new__.__defaults__ = (None,) * len(T._fields)
    if isinstance(default_values, Mapping):
        prototype = T(**default_values)
    else:
        prototype = T(*default_values)
    T.__new__.__defaults__ = tuple(prototype)
    return T


backlink_data = namedtuple_with_defaults('Backlink', ['url', 'backlink', 'a_links', 'img_links', 'err'], [None, None, [], [], False])


def check_url_backlink_exist(url, backlink, a_flag=True, img_flag=False):
    try:
        headers = {'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:22.0) djinn Gecko/20100101 Firefox/22.0'}
        req = Request(url, data=None, headers=headers)
        dtfd = urlopen(req)
    except Exception, e:
        log.warning("URL: %(url)s could not be fetched: error -> %(error)s" %
                    {'url': url,
                     'error': str(e)}
                    )
        dtfd.close()
        return backlink_data(url=url, backlink=backlink, err=True)
    
    resp = dtfd.getcode()
    if resp == 200 and dtfd.info()['Content-type'].startswith('text/html'):
        sp = Soup(dtfd.read())
        a_list, img_list = [], []
        if a_flag == True:
            a_list = sp.findAll('a', href=re.compile('^%s' % backlink))
            a_list = [(a.text, a['href']) for a in a_list]
        if img_flag == True:
            img_list = sp.findAll('img', src=re.compile('^%s' % backlink))
            img_list = [(img['alt'], img['src']) for img in img_list]
        return backlink_data(url=url, backlink=backlink, 
                             a_links=a_list, img_links=img_list)
    else:
        return backlink_data(url=url, backlink=backlink, err=True)

def main():
    usage = "usage: %prog [options] -b http://<url> --url urls.txt -l backlinks.log"
    parser = OptionParser(usage=usage)
    parser.add_option("-u", "--url", dest="url_filename",
                      help="List of URLS to be checked", 
                      metavar="FILE")
    parser.add_option("-l", "--log", dest="log_file",
                      help="Log file where the data will be written. By default writes to /tmp/backlink.log",
                      metavar="FILE", default="/tmp/backlink.log")
    parser.add_option("-b", "--backlink", dest="backlink",
                      help="backlink to be checked",
                      type="str", metavar="URL")
    (options, args) = parser.parse_args(sys.argv)
    if not options.url_filename:
        parser.error("URL file is needed")
    if not options.backlink:
        parser.error("Backlink is needed")

    hdlr = logging.FileHandler(options.log_file)
    formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
    hdlr.setFormatter(formatter)
    log.addHandler(hdlr) 
    log.setLevel(logging.DEBUG)
    try:
        urlfd = open(options.url_filename)
    except Exception, e:
        log.error("URL file is not available %(error)s" % {'error', e})
        sys.exit(1)
    for row in urlfd.readlines():
        row = row.strip()
        # There is no easy way to validate url but to check by sending request
        dt = check_url_backlink_exist(row, options.backlink)
        for text, link in dt.a_links:
            log.info("URL: %s with backlink: %s: Found a tag text: %s with url: %s" % (row, options.backlink, text, link))
        for text, link in dt.img_links:
            log.info("URL: %s with backlink: %s: Found img tag text: %s with url: %s" % (row, options.backlink, text, link))
        



if __name__ == '__main__':
    main()

Thank you Supreet for writing mature code for me :)